There are many techniques used to test the functionality of laboratory instruments for the purpose of controlling the quality of laboratory testing services. One common practice is to test a stable specimen having predetermined characteristics (also known as a quality control specimen) and verify that the test result falls within a predicted range of acceptable values (also known as a control range) for a specified laboratory test. Typically, the control range is either derived from the manufacturer of the quality control material, arrived at by internal laboratory testing (i.e., by applying internal laboratory statistical data to a control rule), or a combination of the two. If the test result falls within the control range, the laboratory instrument is deemed to be functioning properly and is thus suitable for testing actual patient specimens. On the other hand, the laboratory instrument is deemed to be malfunctioning if the test result does not fall within the control range. This practice is referred to as the internal quality control program of the laboratory.
In addition to implementing an internal quality control program, many laboratories participate in external quality control programs (also known as peer-group quality control programs). A typical peer-group quality control program consists of a collection of participating laboratories that test quality control specimens from the same source and submit the test results to a central agency. The central agency then computes group statistical summaries of the submitted test results and sends reports back to the participating laboratories. In this manner, each participating laboratory is able to review reports that quantify the variation in test results experienced among participating laboratories.
In the past, the participating laboratories would record a month's worth of test results and mail the results to the central agency at the end of the month. This step would take approximately 35 days. The central agency would then compile the test results received from the participating laboratories, compute group statistical summaries of the test results, and mail reports back to the participating laboratories. This step would take approximately 15-25 days. The disadvantage to this practice was that the inherent time delay (approximately 50-60 total days) limited the usage of the reports to a retrospective look at the quality of the testing services provided by the participating laboratories. As a result, even if the reports indicated a malfunction of a particular laboratory instrument, hundreds or thousands of actual patient specimens may have already been tested by the instrument.
With the advent of the Internet and other communication networks, many peer-group quality control programs are now able to process test results dynamically on a real-time basis. In practice, a participating laboratory transmits test results to the central agency over the Internet on a regular basis. The central agency then receives the test results, updates the group statistical summaries to include the newly transmitted test results, and immediately transmits reports back to the participating laboratory over the Internet. The advantage to this practice is that the participating laboratory receives the reports in a much timelier fashion than the previous mail-in approach.
Traditionally, the internal quality control program of a laboratory has functioned independently of the external quality control program. The reports received from the central agency (whether in hard-copy form via mail or in electronic form via the Internet) are typically reviewed by someone in a managerial role within the laboratory for the purpose of identifying extreme variations between the data in the group statistical summaries and the internal laboratory statistical data used for internal laboratory testing. If only small variations are detected, nothing is done to the laboratory test system and the internal quality control program remains unchanged. However, if extreme variations are detected, it may provoke an inquiry as to the origin of the variations to thereby trigger a re-calibration of one or more laboratory instruments. Thus, the external quality control program is only utilized to correct large errors in the laboratory test system, while ignoring smaller and more tolerable errors.